Device for mooring ships



March 17, 1970 3, ERZEN 3,500,484

DEVICE FOR MObRING SHIPS Filed Nov. 6, 1968 4 Sheets-Sheet 1 f'i'g.1

c. A. E RZEN' mavrcz FOR uoonme SHIPS.

Much 17, 1970 4 Sheets-Sheet 2 mm Nov. 6. 1968 Plum 1!; l

March 17, 1970 c. A. ERZEN 3,500,484

I DEVICE FOR MOORING SHIPS Filed Nov. 6. 1968 4 Sheets-Sheet 4 fig.6

United States Patent 3,500,484 DEVICE FOR MOORING SHIPS Cevdet A. Erzen, The Hague, Netherlands, Mr. Touloukian, 258 Broadway, New York, N.Y. 10007) Filed Nov. 6, 1968, Ser. No. 773,709 Claims priority, application Netherlands, Nov. 10, 1967, 6715247 Int. Cl. 136% 21/52, 21/00 US. Cl. 98 12 Claims ABSTRACT OF THE DISCLOSURE A device for mooring ships offshore, in particular for the transportation of liquids between a ship and the shore, having an upright mast structure rising from the sea bottom to the surface and anchored at its lower end for universal swinging movement and free rotation about its longitudinal axis, the mast structure carrying floats keeping the same in its upright position. A mooring boom is secured to the mast structure below the water level and extends sideways therefrom in a horizontal position which boom carries one or more mooring towers provided with floats and rising upwardly therefrom to a suitable height above, the water level. A 'riser pipe runs upwardly through the mast structure being connected at its lower end to a pipeline running to the shore and being coupled at its upper end to 'a pipe running through the mooring boom and towers for connection with the pipe system of a ship.

BACKGROUND OF THE INVENTION The invention relates to a device for mooring ships offshore, in particular for the transportation of fluid materials, such as oil between a ship and the shore.

The present trend in modern shipping of building tankers for the transport of oil and similar products of ever increasing tonnage has raised the problem that in many cases existing harbour facilities are not adapted to receive and handle such large tankers, and therefore make it necessary to load and discharge these ships offshore. For that reason it has been suggested to mount a terminal platform or similar structure on the sea bottom some distance offshore, which platform is connected by one or more submerged pipelines to suitable shore installations, such as storage tanks, and is provided with one or more flexible hoses for connection to the tankers to be loaded or discharged, which hoses may float on the surface or may be submergeable. Generally, during operation of this known arrangement the ships are moored to mooring buoys arranged in the vicinity of the terminal platform.

SUMMARY OF THE INVENTION The invention has for its main object to provide a device for mooring ships ofi'shore, which may replace the conventional mooring buoys and which at the same time can be adapted for use as a terminal for loading and unloading fluid materials, such as oil. More in particular, the invention has for its object to provide such a mooring device allowing a quick and eflicient mooring and loading or unloading of ships, also in case of a rough sea.

The mooring device of the invention generally comprises a mast structure rising from a fixed base member on the sea bottom to the water surface and pivotally anchored at its lower end to this base member for universal lateral swinging movement and for free rotation about its longitudinal axis, the mast strutcure comprising one or more floats or buloyancy chambers adajacent its upper end tending to keep the mast structure in a vertical position. A mooring boom is secured to the mast structure extending sideways therefrom and likewise comprising "ice float means supporting the boom in a substantially horizontal position. The mooring boom is preferably attached to the mast structure at a distance below the water level, the boom carrying one or more mooring towers rising upwardly therefrom to a suitable distance above the water surface and comprising the boom floating means. The mooring boom can be rigidly secured to the mast structure but preferably the boom is secured to this structure by suitable coupling means allowing the boom to swing relative to the mast structure in a substantially vertical plane through the axis of the mast structure.

The mast structure with the mooring boom connected thereto is thus free to rotate about its longitudinal axis whereby the mooring boom can at all times assume a position in accordance with the prevailing currents. The buoyancy chambers of the mast structure provide an effective stabilizing force in that on a tilting movement of the mast structure with respect to the vertical caused by an external force, these chambers or floats produce a counteracting moment which increases With an increasing deviation of the mast structure from its vertical position. The shock forces exerted on the device by a ship mooring thereto are thus yieldingly and efficiently damped by a tilting movement of the mast structure and by a swinging movement of the mooring boom about the vertical axis of the mast structure.

The mast structure and the mooring boom may each form at least partly an open frame structure with closed hollow structural members, which thus contribute to the buoyancy of these parts. 7

According to a preferred embodiment of the invention, a fixed rigid riser pipe extends vertically upwardly from the sea bottom centrally through the mast structure, which riser pipe is connected at its lower end to a pipeline running to the shore and is connected at its upper end above the water level through a horizontal swivel pipe coupling and a flexible hose to a pipeline extending longitudinally through the mooring boom. This pipe line may be provided with one or more suitable coupling means for connection to a flexible line leading to a moored ship. The mast structure thus forms a kind of protecting cage about the riser pipe, and the swivel pipe coupling at the upper end of the rigid pipe is easily accessible for maintenance and inspection.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be more readily understood and the further objects and advantages thereof will be more apparent when read in conjunction with the accompanying drawings in which FIG. 1 is a side elevational view of an embodiment of the device according to the invention;

FIG. 2 is a sectional view as seen on the line IIII of FIG. 1;

FIG. 3 is a sectional view as seen on the line IIIIII of FIG. 1;

FIG. 4 is on an enlarged scale an elevation and partly a section of the pivotal mounting assembly for anchoring the mast structure of the device of FIG. 1-3 to the sea bottom;

FIG. 5 is a perspective view of a part of another embodiment of the invention, showing the coupling arrangement between the mast structure and the boom; and

FIG. 6 is a cross-sectional view of one of the buffer elements of the device of FIG. 5.

PREFERRED EMBODIMENTS OF THE INVENTION Referring to FIG. 1-3 of the drawings, the mooring device of the invention has as its main components a mast structure 3 rising from the sea bottom 1 to the vater levelatZ, and amooring boom 4 extending. sub-.

.tantially horizontally sideways from the mast structure I and carrying two mooring towers 5 and 6 rising from his boorrrto some distance above the. water-level 2-. [he mast 3, the .boom 4 and the towers 5. and 6 are :arried out as open framestructures of closed .hollow ubular members welded together and filled with air.

The mast structure 3 has a downwardly tapering. shape LS shown and is anchored at its lower end to a foundaion block. 7 on the. sea bottom 1- for universal lateral winging rr overnentv and for free rotational movement bout its longitudinal, axis. The mast-structure has four or ner posts 8.e xtending upwardly and outwardly from be anchored lower mast-end andcarrying two buoyancy :hambers 9. at the wide upper end of the, mast, which hambers are arrangedat two opposite sides of the mast tructure. The buoyancy chambegs extend-partly above he waterlevelZ and are so dimensionedand arranged hatthey exert atall times an upwardly directed force In. the, mast structure, also at the lowest water level 0 be. expected, and thus try to maintain the mast strucure in a vertical position. r

The mooring boom 4 is arranged ow the; water level. In the embodiment shown in the lrawing, the boom is secured to the mast 3 midway f the height of the latter by means of a hinge coniection 10 with horizontal pivot axis. The boom 4 has triangular cross-sectional shape with two upper longiudinal girder members 11 and a lower longitudinal irdermember '12. The mooring tower 5 is arranged t a distance from the mast 3 of about one-third of he length of the boom and the mooring tower 6 is rranged at the free outer end of the boom. The towers 5 nd 6 have a lateral width gradually increasing from the oom upwardly, as shown in FIG. 3, and each carry at :ieir upper end a platform 13 and 14, respectively, spaced t a suitable distance above the water level. As appears rom FIG. 1, the tower 5 rises vertically upwardly andae tower 6 leans slightly upwardly and away from the last 3. Two buoyancy chambers 15 are secured to each awer and are so dimensioned that these four buoyancy hambers together can support the weight of the moorig boom 4 and the two towers 5 and 6. For a better tability the two buoyancy chambers of each tower are ppositely arranged at the sides of the tower running arallel to the boom 4 and, to the same purpose, ballast eights 16 are secured to the boom 4 beneath each Jwerfor moving the centerof buoyancy of themoor- 1g boom assembly to a point below the center of upard pressure. These weights consist of U-shaped tubes lled with concrete, The mooring boom assembly is" so alanced that in the state of equilibrium practically.

as a bend at its lower end passing through the block 7 r connection with a pipeline 19 running along the sea. ottom to the shore. The riser 18 extends upwardly past 1e upperen'd of the mast 3 and is connected at its upper 1d, by means of a swivel pipe coupling 20, to aU-shapedtterally extending pipe section 21 which can thus rotate the boom.4 if only. the pipe section has sutficient room some distance befor lateral play to allow for. lateral swinging movements of the mast structure. A flexible hose 24 connects the outward end of the pipe section 21 to a rigid pipe section 25 fixedly mounted on the mooring boom,4, which pipe section 25 runs'downwardly'for connection to the lower tubular girder' 'l2 of the boom structure, this girder thus forming part of the pipe line system. This'hollow girder 12 is connectedat itsouter end with one ofthe upwardly extending tubular structural members 26 of the mooring tower 6 which tube 26 leads to the platform 14. A pivotal structure 27 is mounted onthis' platform and a number, of'lioses' 28 are suspended from this portal which hoses are each connected to the pipe line 12, 26 so obtained and are provided with pipe couplings for connection with the pipe system of ashipto be loaded ordischarged. Obviously, 'in'a similar way a branch line may be 'run" from the hollow girder '12 through the tower 5 to the platform 13 (not shown). A-tankermay thus moor to the platforms 13and'14 and may be loaded or discharged through the above described pipe line system running through the riser 18, the boom 4and one or,both of the towers 5 and 6.-

1 FIG. 4 shows the pivotal mounting assembly for'securing'the tapering lower end of the 'maststructure 3 to the foundation block 7-; The concrete block 7 has a circular circumferential shape and "is mounted on a circular row of foundation piles 29 arranged inthe bottom 1. The

- block 7 carries a "steel base plate 30 with an annular V inner wall or metal shell of the-annular upper structure 31,

said track 35 projecting radially inwardly from this inner wall. An annular carriage 36 is arranged in the space enclosed by the upper structure 31 which carriage comprises a number ofrollers 37 journalled on circumferentially spaced shafts radially extending from the annular carriage 36. Therollers 37 are enclosed between and run on the tracks 33 and 34 and allow the carriage to rotate about its vertical 'axis. The carriage is provided at its cir-' cumference withv a further setof rollers38-journaled on vertical shafts and positioned in a common horizontal plane which rollers 38 run on the rail track 35 and thus hold the carriage against radial displacement.

The, carriage 3.6 has two diametrically opposed vertical supports '39 betweenwhich a-hinge ring 40 is mounted for pivotal movement about a horizontal pivot axis 41 whichdntersects the vertical axis of the carriage. The hinge ring 40 is likewise provided with two, upwardly projecting supports 42 between which a carrier ring 43 is 1 mounted for pivotal movements about a pivot axis 44 l a horizontal plane. Two posts 22 on thebuoyancy iambers 9 and slack cables 23 connect the pipe section [to themast structure 3 whereby the pipe section is lade to follow the rotary movements of the mast struclre about, its axisand thus is maintained in a-position Ktendingsubstantially in the same direction as the moorlg boom 4. Obviously, .othermeans may be used for.

eeping the pipe section 21 in the general direction of' the parts 36, 40an'd 43, respectively.

which-extends-perpndicularlyto the pivot axis 41 and likewise intersects the vertical axis of the carriage 36. The upwardly extending corner posts 8 of the mast structure 3 are welded to the' upper'side of this carrier ring 43. The

- above described pivotal mounting assembly thus allows the mast/structure 40'to rotate about its longitudinal axis by means of the rotatably mounted carriage 36, and to make limited swinging movements with respect to the vertical by means of the pivotally' mountedintermediate hinge ring 40and'carrier ring 43. In case larger swinging movements of theinast. structure are desired than the schematical showing of the assemblyjof FIG. 4 would allow, it is of course possible to increase the vertical spacing between As shown in FIG. 4, the rigid riser 18,.passin'g with a bent portion through the foundation block 7, extends vertically upwardly along the axis of the carriage 36 and thus centrally through this carriage and the two rings 40 and 43.

As appears from FIG. 3, a ship 44 can be moored alongside the mooring boom 4 by means of 'bollards 45 or the like arranged on the platforms 13 and 14. On account of the rotatable mounting of the mast structure 3, the mooring boom 12 with the ship moored thereto is free to swing in a horizontal plane to an angular position in which it extends in the direction of the current and the waves. The forces exerted on the mooring device are therefore considerably smaller than in the case of a fixedly supported mooring device which must also be able to resist transverse wave and wind forces acting on the side of the ship.

If transverse forces are exerted on the mast structure, for instance when a ship is being moored, the mast structure can yield by a tilting movement in which the buoyancy chambers 9 to one side of the assembly are further submerged and at the opposite side are lifted from the water. Thereby a counter moment is created which increases with the degree of tilting and which efliciently damps the impact forces of the ship.

The mooring device of FIG. 5 is similar to the device of the FIGS. 1-4 except for the way the mooring boom 4 is secured to the mast structure 3. In the embodiment shown schematically in FIG. 5, the boom 4 is connected to the posts 8 on one side of the mast 3 by means of a resiliently yieldable coupling arrangement generally indicated by 46. This coupling arrangement consists of a number of rod-like link members 47-52 each comprising two tubular rods 53 and 54 which are slidably connected by a shock-absorbing buffer element 55 arranged therebetween as shown in greater detail in FIG. 6. The link mem-' bers 47-52 are each pivotally connected at their opposite ends to the mast 3 and the boom 4, respectively, by means of plural swivel joints generally indicated by 56a56e which allow the link members to swing freely in all directions with respect to the mast or boom, respectively. These swivel joints may be of any suitable known structure and are, therefore, not shown in detail.

As shown in FIG. 5, the link member 47 extends between the swivel joint arranged at 56a on one of the corner posts 8 of the mast to the swivel joint arranged at 56c at the inner end of the lower boom girder 12. Similarly, the link member 48 extends between the swivel joint arranged at 56!) on the adjacent mast comer post 8 to the same swivel joint at 560 on the girder 12. The swivel joints 56a and 56b are arranged at the same locations at the hinges 10 of FIG. 1. The link members 47 and 48 together with a crossbeam 57 between the said corner posts 8 thus form a triangular structure.

The link member 49 extends'from the swivel joint at 56a to the swivel joint arranged at 56d at the opposite inner end of the relevant upper girder 11 of the boom 4 and the link member 50 extends from the swivel joint at 56b to the swivel joint arranged at 56e at the inner end of the other upper boom girder 11, the members 49 and 50 together with the crossbeam 57 and a crossbeam 58 running between the upper girder ends forming a quadrangular structure. The link members 51 and 52 are arranged as diagonals of this structure and extend between the swivel joints 56a and 56e, and 56b and 56d, respectively. Trusses 59 fixedly connect the ends of the upper boom girders 11 with the end of the lower girder 12, forming a triangle with the crossbeam 58.

As also shown in FIG. 1, the pipe section 25 connected to the lower boom girder 12 is secured adjacent its upper end to the upper ends of two substantially vertical frame members or posts .60 extending upwardly from the upper boom girders 11, these posts 60 and pipe section 25 together forming an upwardly projecting rigid structural frame portion at the inner end of the boom 4.

As shown in FIG. 5, a further resiliently yieldable coupling arrangement, generally indicated by 61, is arranged at a slight angle to the horizontal between the mast 3 and the posts about midway of the height of the latter. This coupling arrangement 61 is similar to the above described quadrangular structure of the coupling arrangement 46 and comprises as shown link members 62 and 63 extending between swivel joints at 56 and 56h, and 56g and 56i, respectively, and diagonal link members 64 and 65 extending between the swivel points at 56] and 56i, and 56g and 5611, respectively, the swivel joints 56 and 56g being arranged on the posts 8 of the masts 3 and the swivel joints 56h and 56i being arranged on the posts 60.

As shown in FIG. 6, each shock-absorbing buffer ele- -ment 55 arranged in the link members 47-52 and 62-65 comprises a cylinder 66 closed at one end by a closure plate 67 to which the tubular rod section 53 is fixedly secured, for instance by welding. Approximately midway of its length the cylinder 66 has a second closure plate 68 provided with a central bore which slidingly and sealingly receives a piston rod 69 of a piston 70 arranged for sliding movement in the cylinder bore between the plates 67 and 68. At its outer end the piston rod 67 is fixedly secured to the tubular rod section 54 which is telescopingly received in the open-ended cylinder portion extending past the plate 68 and thus forming a guide for the rod section 54 in its sliding movements with respect to the cylinder 66.

Coil springs 73 and 74 are arranged in the cylinder chambers on both sides of the piston 70 between this piston and the plates 67 and 68, respectively, which springs tend to maintain the piston in its midposition.

The cylinder chambers enclosed between the piston 70 and the plates 67 and 68, respectively, are filled with a suitable liquid, such as oil, and are connected through a bypass conduit comprising a throttle or control valve 76. The conduit 75 opens into the cylinder chambers opposite the stop members 7.1 and 72 at the ends thereof. The outwardly turned ends of the rod sections 53 and 54 (not shown in FIG. 6) are each connected to one of the swivel joints 56a-56i as above described with respect to FIG. 5.

When an external force is exerted between the rod sections 53 and 54, the piston 70 will be moved to the right or to the left, as seen in FIG. 6, depending on the direction of this force and against the action of the spring 73 or 74 which is being compressed by this movement. The movement of the piston 70 is damped in a known manner by the oil in the cylinder which is displaced by the piston and is forced to flow from the one cylinder chamber to the other through the bypass conduit 75 and through the adjustable flow restriction formed by the control valve 76. Instead of the bypass conduit 75, one or more 'small holes may be provided in the piston 70 in a known manner. Instead of oil, another suitable liquid, for instance sea water, may be used in the cylinder. If desired, a further spring may be arranged in the cylinder space enclosed between the outer face of the plate 68 and the inner end of the rod section 54.

The above described resiliently yieldable coupling arrangements 56 and 61 with buffer elements 55 constitute an eflicient damping means for absorbing part of the impact energy transmitted to the boom and mast by a ship being moored or by the action of the waves and wind. Thereby the high peak stresses which would otherwise occur in the connection between the mast and the boom are efliciently reduced. Also, this coupling arrangement provides a limited freedom for the mooring boom to rise and fall with the tide while substantially maintaining its horizontal position.

While the invention has been shown and described with reference to specific embodiments thereof, it will be understood that other embodiments may be resorted to.

What is claimed is:

1. A device for mooring ships offshore, comprising a mounting base member arranged on the bottom below a body of water, an upright mast structure extending up- Wardly from said base member to above the water level,. neans for pivotally anchoring said mast structure at its ,ower end to said base member for universal lateral swingng movement and free rotational movement about is ongitudinal axis, said mast structure comprising first ioat means tending to keep said structure in a vertical position, a mooring boom extending sideways from said nast structure, and means securing said boom to said nast structure, said mooring boom comprising second loat means tending to support said boom in a substan- ;ia1ly horizontal position.

2. The device of claim 1, in which said mooring boom .s secured to said mast structure below the water level at 1' distance from the mast structure upper end, said moor-., lng boom further comprising at least one mooring tower extending upwardly therefrom to a selected height above said water level, said tower comprising at least part of raid second float means.

i 3. The device of claim 2, in which said mooring boom is provided with ballast means below said mooring tower. 4. The device of claim 1, in which said mooring boom iecuring means comprises hinge means allowing said nooring boom to swing with respect to said mast struc- ;ure in a plane substantially through said longitudinal axis of the latter. 5. The device according to claim 4, in which said moor- .ng boom securing means includes a resiliently yieldable :oupling arrangement comprising a plurality of link mem- Jers extending between said mast structure and the inner and of said mooring boom, and a plurality of swivel joint neans connecting said link members to said mast struc- ;ure and boom, respectively, said link members comprisng spring-loaded shock-absorbing buffer members allow-- ng said link members to be resiliently longitudinally ex- :ended and compressed by external forces acting on said rigid riser pipe extending vertically upwardly from said.

Jase member centrally through said mast structure and adapted to be connected atits lower end to a pipeline running to the shore, a rotary pipe coupling means mounted on the upper end of said riser pipe above the about the circumference of said carriage means in a com- 35 Water level, flexible conduit means communicating at one end through said pipe coupling means with said riser pipe, a pipeline connected to the other end of said flexible conduit means and running outwardly, away from said mast structure through said mooring boom, and pipe coupling means connected to the outer end of said moor,- ing boom pipeline and adapted for connection to an ex -f ternal flexible conduit leading to a ship. i

The device of claim '8, in which said moorin'g boom, comprises a. longitudinally extending tubular structural, element, said latter element forming part of said-mooring boom pipeline.

10. The device of claim 1, in which said anchoring means, for, said mast structure comprises a. horizontal annular carriage means, mounted in said base member for rotation about a vertical axis, first annular member pivotally mounted on said carriage means for swinging movement about a first horizontal pivot axis, and a second annular memberpivotally mounted on said first annular member. for swingingmovement about a second pivot axis perpendicular to said first pivot axis, the lower end of said mast structure being fixedly secured to said second annular member. Y

11. The device of claim 10, in which said base member has a cylindrical recess, two spaced circularguide rails of equal diameter mounted coaxially one above the other in said recess and. a third circular guide rail mounted in. said recess coaxially with said first two guide rails, saidv carrage means comprising a first group of vertically mounted wheels arranged equally spaced from one another about the circumference of said carriage means and enclosed between said first two guide rails for running therebetween, and a second group of wheels mounted mon horizontal plane and running on said third circular guide rail whereby said carriage means is held in said base member against radial and vertical movement.

. -12. The deviceof claim 11, in which said first float References Cited UNITED STATES PATENTS "3,380,991 4/1968 Saurin et a1. 3,409,055 11/1968 Bily..

TRYGVE M. BLIX, Primary Examiner j r i. me 1; 114-230 j 

